[rich2468]

Yes.....when the front shell rear arm on the door side is too low (there's no gap between the top shell and the lower "box" at the door jamb assembly) the weight of the top shell pushes the door striker plate too low....

Eventually there's no way to compensate for the corner of the front shell being too low via adjusting the leveling jack in front of the door....which is just changing the lower door geometry. (That point is when the bottom "ledge" of the door will no longer clear the threshold).

See the gap between the two shells in the attached picture (which is not my TrailManor).
-When the front shell has settled and the gap is gone, it's time for an adjustment of the rear lift arms of the front shell.